Metallic bulb lamp



June '17, 1941. G, OLL AY 2,245,782

' METALLIC BULB LAMP Filed Dec. 8, 1936 2 Sheets-Sheet 1 INVENTOR 6. c.#0110/1 4).

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ATTO R N EY June 17, 1941. c OW 2,245,782

METALLI C BULB LAMP Filed Dec. 8, 1936 2 Sheets-Sheet 2 ATTORNEYPatented June 17, 1941 METALLIC BULB LAMP Gilbert 0. Holloway,Bloomfield, N. J., assignor to Westinghouse Electric & ManufacturingCompany, East Pittsburgh, Pa., a corporation of Pennsylvania ApplicationDecember 8, 1936, Serial No. 114,746

16 Claims.

This invention relates to incandescent electric lamps and moreparticularly to such in which each has a glass window or lens in a metalbody that may be in the form of a parabolic reflector.

In constructing lamps for projection purposes, such as automobileheadlight lamps, it is extremely desirable that the filament be of theconcentrated variety and so positioned that when the lamp is mounted,the filament will be centered or disposed at the focus of the associatedreflector. In most lamps, for such a purpose, the filament is disposedin a predetermined relation with respect to the lamp base, so that whenthe base is normally disposed with respect to a reflector or the like,the filament will be in proper position.

In accordance with my invention I propose to construct a lamp, adaptedfor projection purposes such as for automobile headlights, in which thefilament is positioned during the course of manufacture at the focus ofthe reflector, the reflector itself being incorporated as a part of thebulb.

It will therefore be seen that it is one of the objects of my inventionto produce an incandescent electric lamp having a bulb formed of ametallic reflector portion and a transparent window portion sealedthereto, with a concentrated filament centered with respect to saidreflector portion and sealed in said bulb.

Another object of my invention is the provision of an incandescentelectric lamp suitable for projection purposes and consisting, in themain, of metal parts which may be assembled by highspeed welding.

A further object of my invention is the provision of an incandescentelectric lamp comprising a mount including a concentrated filament,flanges adapted to be welded to a lamp bulb, and an exhaust tube portionwhich may be closed by welding.

A still further object of my invention is the manufacture of a higheiflciency lamp for projection purposes, including a reflector which issealed in the bulb so that it cannot become tarnished or dirty, and aconcentrated filament centered with respect to said reflector during thecourse of manufacture.

Other objects and advantages of the invention, relating to theparticular arrangement and construction of the various parts, willbecome apparent as the description proceeds.

Referring to the drawings illustrating my invention, the scope whereofis defined by the appended claims:

Fig. 1 is an axial sectional view of one form of lamp embodying myinvention.

Fig. 2 is a fragmentary view of the lamp on the line 11-11 of Fig. 1,looking in the direction of the arrows.

Fig. 3 is a view corresponding to Fig. 1, but showing the parts of thelamp separated from one another, with portions in elevation.

Fig. 4 is an elevational-view illustrating another embodiment of myinvention.

Fig.5 is a view corresponding to Fig. 1, but showing a modification.

Fig. 6 is a bottom plan view of the embodiment of Fig. 5.

Fig. 7 is an elevational view, partly an axial section, of a flashlightincorporating a lamp in accordance with Figs, 5 and 6.

Fig. 8 is an axial sectional view of a further embodiment of myinvention, portions being shown in elevation.

'Referring to the drawings in detail, like parts being designated bylike reference characters, and first considering the embodiment of myinvention illustrated in Figs. 1, 2, and 3, there is shown a lamp incomprising a bulb ll formed generally of two parts; that is, acup-shaped reflector portion l2, desirably composed of metal, and arelatively flat transparent window or lens portion l3 desirably formedof glass. The edge of the lens or window portion I3 is shown secured, asby fusion, to a rim portion I4, formed of Kovar," for example, or othermetal having a coeflicient of expansion corresponding with that of theglass used, and therefore sealable thereto. The rim portion I4 is, inturn, secured to the outer peripheral portion of the reflector portion12 in any desired manner, for example, by welding, as indicated at l5.

The bulb II has sealed thereinto a concentrated filament I6 desirablyforming part of a mount H, the body portion of which may be a metal discill with its outer peripheral portion flanged as indicated at l9, andtelescoped with respect to corresponding flange portion 20 of thereflector I2, which defines a central filamentreceiving opening 2|.

' The filament may be supported from the metal disc l8 by leads 22 and23, the lead 22 being desirably welded to the disc [8, and therebyelectrically connected thereto, and the lead 23 desirably passingthrough a glass bead or other insulating portion 24 closing an aperture25 in said disc I8. The disc [8 desirably carries an exhaust tube 26which may be formed of metal as part of said disc, or of glass or othersuitable material, as desired.

A base 21, which may be of generally usual construction and compriseametal shell 28 and an insulating portion 29 of glass or the likecarrying a central conductive contact 30, may be employed. The metalshell 28 desirably carries one or more lamp securing lugs 3| of usualform and telescopes with respect to the flange 20 of the reflector I 2.

In assembling the parts of the lamp I0, the lens I3 is sealed withrespect to the reflector I 2, the mount ll positioned as shown in Fig.1, and welded or otherwise sealed to the flange 20 of the reflector l2,as indicated at 32, in such position that the center of the filamentcorresponds with the focal point of the preferably parabolic reflector[2.

On account of this method of manufacture it will be clear that thefilament is readily positioned in the proper location as the lamp isbeing manufactured, so that there is no possibility that it will be bemisplaced with respect to the reflector during the life of the lamp.This is a distinctive feature of the present lamp in that there is noessential predetermined relation between the base and the filament, butrather between the reflector and the filament, which is the ultimateobjective of precision basing.

After sealing the amount with respect to the reflector portion of thebulb ll, exhausting by means of the tube 26, and tipping-01f asindicated at 33, the lead 23 is drawn through the tubular contact member30, and the base 21 applied, as indicated in Fig. 1, and welded orotherwise secured to the reflector portion I2 of the bulb, as indicatedat 34.

In view of the foregoing description, it will be seen that I havedevised a highly efficient lamp for projection purposes, including areflector as part of its bulb and with a filament centered with respectto said reflector during the course of manufacture. If desired to employthe lamp with a larger or more extensive reflector, such as designatedby reference character 35 in Fig. 4, the same may be secured to the edgeportion l4 of the lamp Ill by any suitable securing means, as indicatedat 35, without disturbing the lens l3 of said lamp. The supplementalreflector 35 may be employed with an outerlens 31, as illustrated.

Referrin now to the embodiment of my invention illustrated in Fig. 5,there is shown a lamp l comprising a bulb I l consisting of a cupshapedreflector portion I2 desirably formed of metal, and a relatively flattransparent window or lens portion I3 desirably formed of glass. In thepresent embodiment the reflector portion I2 is formed of Kovar, forexample, or other metal having a coeflicient of expansion correspondingwith that of the glass used, so that its peripheral edge portion may bedirectly sealed to said glass as illustrated.

The central portion of the reflector [2 is apertured as indicated at 2|a and secured or sealed thereto, as by means of welding, is an annularor circular plate 38 forming an outstanding peripheral flange, as shown.The plate or flange portion 38 need not be of any special metal, such asKovar as it is not sealed directly to glass, but rather to a specialform of base 39, as illustrated.

The base 39 comprises a preferably circular metal plate 40, with aninwardly or upwardly embossed central portion 4|, fitting the aperture2! and desirably carrying an exhaust tube 26.

The bulb H has sealed thereinto a concentrated filament I6, as in thefirst embodiment desirably forming part of a mount which is incorporatedas a part of the base 39 and includes leads 22 and 23. The lead 22 isdesirably welded to the embossed portion 4| of the plate 40, and therebyelectrically connected thereto, the lead 23 desirably passing through aglass bead or other insulating portion 24, which may be held in a metalbushing or eyelet 42, if employed, secured to the embossed portion 4t ofthe plate 40, or held directly in said portion 4 I.

Before finally sealing off the bulb II, the inside of the reflectorportion [2 is desirably coated with silver or other metal to form a filmor plating providing the desired light reflecting surface, therebyproviding an eflicient reflection as part of the bulb. After sealing offthe exhaust tube 26 as indicated at 33 the lead 23 may be passed throughthe metal disc member 43 associated with the cylindrical insulating baseelement 44 and soldered thereto, as indicated at 45, thereby holding theinsulating member 44 in place in the base plate 40, as a housing for theexhaust tube 26 The base plate 40 may, if desired, be provided with theusual form of bayonet slots 46, for holding the completed lamp in placein the usual manner.

The assembly of a lamp, such as shown in Figs. 5 and 6, in a flashlight41 is illustrated in Fig. '7. The flashlight comprises a casing 48 and acap 49 threaded to an enlarged portion 50 of said casing, as illustratedand adapted to clamp over the peripheral portion of the lens I? of thelamp l0, after said lamp has been positioned with its slots 46 receivinglocking lugs 5| positioned on the end plate portion 52 of the flashlight41. The lamp Ill is illustrated with its center contact engaging thecenter contact 53 of the associated dry cell 54, the circuit beingcompleted through the switch 55, when the cell at the other end of theflashlight 41 is grounded to the casing 48 and held therein by the cap56.

In this embodiment of the invention it will be seen that a flashlightmay be produced in which the lens and the reflector are part of thelamp, rather than part of the flashlight casing, as heretofore. In thisway duplication of parts is avoided and economy in manufacture obtained.

Referring now to the embodiment of my invention illustrated in Fig. 8, alamp W is illustrated comprising a bulb ll including a cup-shapedreflector portion l2 sealed to a relatively flat lens portion I3 andprovided with an outstanding flange portion 38 all as in accordance withthe embodiment of Figs. 5 and 6. However, the exhaust tube 26 is showncoming through the reflector portion of the bulb rather than through thebase portion, thereby making it possible to simplify the base portion 39In the present embodiment, therefore, the base portion consists merelyof a circular plate 40 with bayonet slots 46", and a central aperturereceiving an insulating member 24, with or without an enclosing metalbushing 42. As in the preceding embodiment a filament I6 of theconcentrated variety, is supported by leads 22 and 23 the former beingwelded to the base plate 40 and the latter insulated therefrom by themeans 24 passing through an insulating disc 29 and secured, as by solder45 to a central contact plate 43 In all forms of my invention the mainor primary reflector is permanently sealed from the atmosphere by thelens or glass window l3, and

' means.

thereby protected from dust and oxidation. It will also be noted that astronger lamp may be provided if the main portion thereof is formed ofmetal and that such metal parts may be assembled by high speed weldingor other desired It will also be understood that the peripheries of thereflector and cover or lens sections are provided with sealing surfacesadapted to abut one another, and that on account of the interflttingrelationship shown, comprising an annular ridge or peripheral portion ofone and a receiving annular groove or cavity in the other,

means are provided for positioning the said sections in predeterminedrelationship transversely with respect to one another.

Although preferred embodiments of my invention have been disclosed, itwill be understood that modifications may be made within the spirit andscope of the invention as defined by the appended claims.

I claim:

1. An incandescent electric lamp comprising a bulb consisting of a metalreflector portion and a window portion having its edge portion sealedthereto, said reflector portion having a central opening opposite tothat covered by the window portion, and a base with associated mountclosing said opening and comprising an inner metal plate sealed to saidreflector portion, a concentrated filament disposed at the focus of saidreflector portion and carried by said plate on a pair of leads, one ofsaid leads being electrically connected to said plate and the other leadpassing through and insulated from said plate, and an exhaust tubeextending from said plate, an outer casing enclosing said exhaust tube,and a central contact carried by said casing and to which said otherlead is connected.

2. A prefocussed incandescent electric lamp comprising a bulb consistingof a reflector portion and a window portion sealed thereto, saidreflector portion having a central opening opposite to that covered bythe window portion and defined by a generally cylindrical flange, and abase with associated mount closing said opening and comprising an innermetal plate sealed to said reflector portion and having a generallycylindrical flange telescoping with said reflector portion flange, afilament carried by said plate on a pair of leads one of said leadsbeing electrically connected to said plate and the other lead passingthrough and insulated from said plate, an outer casing for said basehaving a generally cylindrical flange telescoping over said reflectorportion flange, and a central contact carried by said casing and towhich said other lead is connected.

3. An incandescent electric lamp comprising a bulb formed of a windowportion and a reflector portion, said reflector portion having a centralopening opposite to that covered by said window portion, and a flatannular plate directly secured to the edge defining said central openingso that it outstands from said reflector portion as an external flangefor supporting the filament mount.

4. An incandescent electric lamp comprising a bulb formed of a windowportion and a reflector portion, said reflector portion having a centralopening opposite to that covered by said window portion, and a metalmount and base secured to said annular portion and comprising leadscarrying a concentrated filament disposed at the focus of saidreflector, one of said leads being electrically connected to said baseand the other insulated therefrom and passing therethrough, an

exhaust tube portion extending through said base portion, and aninsulating cylindrical portion telescoping in said base portion andcovering said exhaust tube, said insulated filament lead extendingthrough said cylindrical portion and forming a central contact for saidlamp.

5. A flashlight comprising a casing, one end portion of which isenlarged forming a socket for a lamp, an incandescent electric lampsecured in said socket portion and comprising a bulb formed of a cupshaped reflector portion and a relatively flat window portion, and anannular clamp threaded to the socket end of said casing and having anouter rim formed with an inwardly projecting annular flange overlyingand directly engaging the edge of said window portion for holding thelamp in place in said socket.

6. A flashlight comprising a generally cylindrical casing, one endportion of which is enlarged forming a socket, a lamp disposed in saidsocket portion and comprising a bulb formed of a lens and a reflectorportion, and a filament centered with respect to said reflector portionand sealed in said bulb, and means for mounting said filament, a portionof which mounting means is formed as a base secured in said socket, anda clamp threaded to the enlarged portion of said casing and providedwith a rim overlying the 4 edge portion of said lens for holding thelamp in place in said socket.

7. A prefocussed incandescent electric lamp comprising a bulb formed ofa metallic reflector portion and a window portion sealed thereto, saidreflector portion having a central opening opposite to that covered bythe window portion, and a metal mount carrying leads supporting aconcentrated filament, said mount having a peripheral flange telescopedwith respect to the central opening of, and directly secured to, saidreflector portion.

8. A prefocussed electric lamp comprising a bulb formed of a metallicreflector portion hav ing a central opening for receiving a filamentmount and an outer rim, a window portion sealed to said outer rim, afilament mount closing said central opening and so positioned that thefilament is central with respect to said reflector portion, and a basetelescoping with respect to said reflector and directly secured to saidreflector portion, covering said mount, and comprising an outer shellconnected to one side of said filament, and a central insulated contactconnected to the other side.

9. An incandescent electric lamp comprising a bulb, consisting of alens, a rim of metal having an appropriate coeflicent of expansion andformed with a cylindrical flange embedded in the inner surface portionof said lens within but near to the edge portion thereof and anoutstanding annular flange underlying and extending beyond said edgeportion, and a reflector portion welded to said annular flange, and aconcentrated filament centered with respect to said reflector portion.

10. An incandescent electric lamp comprising a bulb formed of a metallicreflector portion and a window portion sealed thereto, said reflectorportion having a central opening opposite to that coveredby said windowportion, and a metal mount carrying leads supporting a concentratedfilament, said mount having a peripheral flange telescoped with respectto the central opening of said reflector and secured in such positionthat the center of the filament corresponds with the focus of thereflector, and a base telescoping with respect to said reflector,covering said mount, and comprising an outer 'shell connected to oneside of said filament and a central insulated contact connected to theother side.

11. An incandescent electric lamp comprising a bulb formed of a windowand a reflector portion, said reflector portion consisting of metalhaving a coefiicient of expansion corresponding with that of the windowand having an outer edge, said window receiving said edge of thereflector portion embedded in its inner surface adjacent its periphery,and a filament centered with respect to said reflector portion andsealed in said bulb.

12. An incandescent electric lamp comprising a bulb formed of a windowportion and a reflector portion, said reflector portion being formed ofmetal having a coefficient of expansion corresponding with that of thewindow portion, said window portion having its edge portion secured tosaid reflector portion, said reflector portion having a central openingopposite to that covered by said window portion, and an annular platesecured to the edge defining said central opening,

so that it outstands from said reflector portion as a flange.

13. An incandescent electric lamp comprising a bulb formed of a windowportion and a reflector portion, said reflector portion being formed ofmetal having a coefficient of expansion corresponding with that of thewindow portion, said window portion having its edge portion secured tosaid reflector portion, said-reflector portion having a central openingopposite to that covered by said window portion, an annular platesecured to the edge defining said central opening, so that it outstandsfrom said reflector portion as a flange, and a metal mount and basesecured to said annular portion and comprising leads carrying aconcentrated filament disposed at the focus of said reflector, one ofsaid leads being electrically connected to said base and the otherinsulated therefrom and passing therethrough, an exhaust tube portionextending through said base portion, and an insulating cylindricalportion telescoping in said base portion and covering said exhaust tube,said insulated filament lead extending through said cylindrical portionand forming a central contact for said lamp.

14. A flashlight comprising a casing one end portion of which isenlarged forming a socket for a lamp, an incandescent electric lampsecured in said socket portion and comprising a bulb formed of a cupshaped reflector portion and a relatively flat Window portion, saidreflector portion having a metal light-reflecting surface and sealed tosaid window portion, and an annular clamp threaded to the socket endofsaid casing and having an outer rim formed. with an inwardlyprojecting annular flange overlying and directly engaging the edge ofsaid window portion for holding the lamp in place in said socket.

15. A flashlight comprising a generally cylindrical casing one endportion which is enlarged forming a socket, a lamp disposed in saidsocket portion and comprising a bulb formed of a lens and a reflectorportion, said reflector portion being of metal having a coeflicient ofexpansion corresponding with that of the lens, said lens having its edgeportion fused to said reflector portion, and a filament centered withrespect to said reflector portion and sealed in said bulb, a mount forsaid filament, a portion of which is formed as a base secured in saidsocket, and a clamp threaded to the enlarged portion of said casing andprovided with a rim overlying the edge portion of said lens for holdingthe lamp in place in said socket.

16. An incandescent electric lamp comprising a bulb formed of a metallicreflector portion and a window portion sealed thereto, said reflectorportion having an inner metallic surface and a central opening oppositeto that covered by said window portion, and a metal mount carrying leadssupporting a concentrated filament, said mount having a flange portiontelescoping in said central opening and directly secured to thereflector in such position that the center of the filament correspondswith the focus of said reflector, and a base portion secured to saidreflector, closing said opening, covering the outer portion of saidmount, and comprising a shell formed with a central insulated contactconnected to one side of said filament and with its edge portion securedto the peripheral edge defining said opening.

GILBERT C. HOLLOWAY.

